Effect of Withania somnifera and Asparagus racemosus Supplementation on In Vitro Gas Production, Substrate Degradation and Methane Emission

Oviya, A., Dutta, N., Kaur, N. and Jadhav, S.E. 2025. Effect of Withania somnifera and Asparagus racemosus supplementation on in vitro gas production, substrate degradation and methane emission. Animal Nutrition and Feed Technology, 25: 373–380. This study was performed to ascertain the supplementary effect of Withania somnifera (WS; Ashwagandha) and Asparagus racemosus (AR; Shatavari) on in vitro gas production, substrate degradation and methane emission in cattle inoculum. The concentrate mixture, wheat straw and green maize fodder (60:20:20 on dry basis) were used as a substrate and WS and AR were incorporated at the levels of 0, 1.0, 2.0 and 3.0%. Further, combinations of WS and RA at various ratios such as 1:1, 1:2 and 2:1 were incorporated at 0, 1.0 and 2.0% levels. The supplementary effect of WS and AR on substrate degradation revealed significant (P<0.05) enhancement in gas production, truly degraded organic matter in the rumen (TDOMR), microbial biomass production (MBP) and partitioning factor (PF) than the unsupplemented group (CON). The effect of herbal combinations on substrate degradation revealed that gas production and TDOMR were significantly (P<0.05) higher at 2:1 ratio of WS and AR followed by 1:1 and 1:2 ratios relative to CON. The MBP and PF were significantly (P<0.05) higher in all the herbal combinations groups than CON. The inclusion of WS and AR (2:1) at 1.0% manifested significant (P<0.05) reduction in methane emission followed by WS and AR at 1.0% level. It may be established that the inclusion of herbs alone or in combination substantially increased substrate degradation and efficiency of MBP. However, the combination of both the herbs at 1.0% level also beneficially reduced methane emission.